Polymer products based on isocyanates, particularly polyurethanes, polyureas, and polyamides, are typically used as coatings, adhesives, elastomers, fibers and foams. These polymer products are classified as segmented block copolymers having hard and soft segments. The hard segments are typically semi-crystalline or amorphous polymeric isocyanate-derivative segments of urethane, urea, and/or amide groups. These hard segments are considered to be the principal load bearing components of segmented block copolymers. The soft segments are flexible polymeric materials that provide impact resistance to the segmented block copolymer. The final morphology of the segmented block copolymer exhibits microphase segregation between the hard and soft segments since the soft and hard segments are chemically linked, but thermodynamically incompatible.
The most commonly used soft segment precursors, elastomers such as polyether and polyester, have oxygen in their backbone. Segmented copolymers containing these soil segments are susceptible to the oxidative and/or hydrolytic degradation and have poor aging resistance. Hydrophobic materials, such as hydroxyl-terminated polybutadiene, have been used to make polyurethanes and polyureas. However, due to the presence of double bonds in the backbone of these hydrophobic elastomers, they have very poor oxidative and thermal resistance.
U.S. Pat. No. 5,162,445 discloses functionalization of isobutylene-co-paramethylstyrene with a number of nucleophilic reagents, including diethanol amine resulting in two hydroxyl groups per functionalized styrenic moiety.
Di-isocyanate has been used to cure copolymers of isobutylene and styrene as described in EP-A2-0 325 997 and EP-A2-0 238 001. Some of the styrene moieties are modified by carboxylic acid derivatives and then by amino alcohols to facilitate curing with isocyanate. EP-A2-0 325 997 and EP-A2-0 238 001 disclose di-isocyanate curing of polymers having a molecular weight of 700 to 200,000. However, none of these disclosures discuss the use of isocyanates in combination with co-reactants to obtain segmented copolymers.
It would be desirable to develop a segmented block copolymer composition that has the strength and load-bearing characteristics of polymeric isocyanate-derivative segments such as polyurethane, polyurea, or polyamide materials, as well as other isocyanate derivatives, while having the flexibility and impact resistance derived from an elastomer. It would be even more desirable if the elastomer was resistant to degradation from oxidation or aging and possessed a high degree of hydrolytic stability and thermal resistance. It would also be desirable if the elastomer was capable of a high degree of chemical bonding with a polymeric isocyanate-derivative segment.